NVIDIA's GeForce 7800 GTX Hits The Ground Running
by Derek Wilson on June 22, 2005 9:00 AM EST- Posted in
- GPUs
No More Memory Bandwidth
Again, we have a 256 bit (4x 64 bit) memory interface to GDDR3 memory. The local graphics memory setup is not significantly different from the 6800 series of cards and only runs slightly faster at a 1.2 GHz effective data rate. This will work out in NVIDIA's favor as long as newer games continue to put a heavier burden on pixel shader processing. NVIDIA sees texture bandwidth as outweighing color and z bandwidth in the not too distant future. This doesn't mean the quest after ever increasing bandwidth will stop; it just means that the reasons we will need more bandwidth will change.A good example of the changing needs of graphics cards is Half-Life 2. While the game runs very well even on older graphics cards like the 9800 Pro, the design is such that increased memory bandwidth is far less important than having more shader processing power. This is why we see the 6600GT cards significantly outperform the 9800 Pro. Even more interesting is that in our testing, we found that enabling 4xAA on a 9800 Pro didn't affect performance of HL2 much at all, while increasing the resolution from 1024x768 to 1280x1024 had a substantial impact on frame rates. If the HL2 model is a good example of the future of 3D engines, NVIDIA's decision to increase pixel processing power while leaving memory bandwidth for the future makes a lot of sense.
On an interesting side note, the performance tests in this article are mostly based around 1600x1200 and higher resolutions. Memory usage at 2048x1536 with 32bit color and z-buffer runs a solid 144MB for double buffered rendering with 4x AA. This makes a 256MB card a prerequisite for this setup, but depending on the textures, render targets and other local memory usage, 256MB may be a little short. PCI Express helps a little to alleviate any burden placed on system memory, but it is conceivable that some games could get choppier when swapping in and out large textures, normal maps, and the like.
We don't feel that ATI's 512MB X850 really brings anything necessary to the table, but with this generation we could start to see a real use for 512MB of local memory. MRTs, larger textures, normal maps, vertex textures, huge resolutions, and a lack of hardware compression for fp16 and fp32 textures all mean that we are on the verge of seeing games push memory usage way up. Processing these huge stores of data require GPUs powerful enough to utilize them efficiently. The G70 begins to offer that kind of power. For the majority of today's games, we are fine with 256MB of RAM, but moving into the future it's easy to see how more would help.
In addition to these issues, a 512MB card would be a wonderful fit for Dual-Link DVI. This would make the part a nice companion to Apple's largest Cinema Display (which is currently beyond the maximum resolution supported by the GeForce 7800 GTX). In case anyone is curious, a double buffered 4xAA 32bit color+z framebuffer at 2560x1600 is about 190MB.
In our briefings on G70, we were told that every part of the chip has been at least slightly updated from NV4x, but the general architecture and feature set is the same. There have been a couple of more significant updates as well, namely the increased performance capability of a single shader pipe and the addition of transparency antialiasing. Let's take a look at these factors right now.
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Johnmcl7 - Wednesday, June 22, 2005 - link
If they're too busy for the article, that's fair enough, the point is they should put it up when they've had time to check it over, rather than rush an article up that isn't ready to be published.John
IronChefMoto - Wednesday, June 22, 2005 - link
Regarding the "shame on Anandtech" comments -- y'all ever think they were too busy sh*tting themselves at the performance of this card to really pay that much attention to the article? ;-)IronChefMorimoto
Johnmcl7 - Wednesday, June 22, 2005 - link
The prices I've seen here in the UK for the 7800s here are around 400 pounds, the 6800 Ultras are currently around 300 pounds. So quite an increase over the NV40s but not unacceptable given the performance, I'm sure they'll come down in price once the early adopters have had their fill.John
yacoub - Wednesday, June 22, 2005 - link
#26 - You must be new to the market, relatively speaking. I remember quite well the days when high-end new videocards were at MOST $400, usually $350 or less when they debuted. It was more than a year or two ago though, so it might have been before your time as a PC gamer.rimshot - Wednesday, June 22, 2005 - link
Not sure why the price is so high in North America, here in Aus you can get a 7800GTX for the same price as a 6800GT ($850AU).nitromullet - Wednesday, June 22, 2005 - link
"What no Crossfire benchies? I guess they didn't wany Nvidia to loose on their big launch day."Ummm... maybe because CrossFire was paper launched at Computex, and no one (not even AT) has a CrossFire rig to benchmark? nVidia is putting ATI to shame with this launch and the availability of the cards. Don't you think if ATI had anything worth a damn to put out there they would?
All that aside... I was as freaked out as the rest of you by these benchmarks at first (well moreso than some actually, becuase I just pulled the $600 trigger last night on an eVGA 7800GTX from the egg). However, these graphs are clearly messed up, and some appear to have already been fixed. I guess someone should have cut Derek off at the launch party yesterday.
blckgrffn - Wednesday, June 22, 2005 - link
Very disapointed at the fit and finish of this article. Anandtech is supposed to have the best one, not a half baked one :( I even liked HardOCP better even with their weird change the levels of everything approach - at least it has a very good discussion of the differences between MS and SS AA and shows some meaningful results at high res as well.Shame on Anandtech :(
fishbits - Wednesday, June 22, 2005 - link
Good release.Can we get a couple of screen shots with the transparency AA?
"Maybe this one of the factors that will lead to the Xbox360/PS3 becoming the new gaming standard as opposed to the Video Card market pushing the envelope."
Yeah, because the graphics components in consoles don't require anything but three soybeans and a snippet of twine to make. They're ub3r and free! Wait, no, you pay for them too eventually even if not in the initial console purchase price. Actually I think the high initial price of next gen graphics cards is a sign of health for PC gaming. There are some folks not only willing to pay high dollars for bleeding edge performance, they're willing to pay even higher dollars than they were in the past for the top performers. Spurs ATI/Nvidia to keep the horsepower coming, which drives game devs to add better and better graphics, etc.
"They only reveresed a couple of labels here and there, chill out. It's still VERY OBVIOUS which card is which just by looking at the performance!"
Eh, I use benchmarks to learn more about a product than what my pre-conceived notions tell me it "ought" to be. I don't use my pre-conceived notions to accept and dismiss scientific benchmarks. If the benches are wrong, it is a big deal. Doesn't require ritual suicide, just fixing and maybe better quality control in the future.
Thresher - Wednesday, June 22, 2005 - link
2x6800GT costs almost the same amount as this single card and gives up nothing in performance.The price of this thing is ridiculous.
rubikcube - Wednesday, June 22, 2005 - link
Just wanted to say thanks for starting your benchmarks at 1600x1200. It really makes a difference in the usability of the benchmarks.